#include "BTreeNode.h"
#include <iostream>
using namespace std;

/*
 * Read the content of the node from the page pid in the PageFile pf.
 * @param pid[IN] the PageId to read
 * @param pf[IN] PageFile to read from
 * @return 0 if successful. Return an error code if there is an error.
 */

BTLeafNode::BTLeafNode()
{   NodePtr->Nextkey = -1;
	NodePtr->Count = 0;
	NodePtr->emptyflag = 0;
	NodePtr=(leafNode*)buffer;}

RC BTLeafNode::read(PageId pid, const PageFile& pf)
{ 
	return pf.read(pid, buffer);
}
    
/*
 * Write the content of the node to the page pid in the PageFile pf.
 * @param pid[IN] the PageId to write to
 * @param pf[IN] PageFile to write to
 * @return 0 if successful. Return an error code if there is an error.
 */
RC BTLeafNode::write(PageId pid, PageFile& pf)
{ 
	return pf.write(pid, buffer);
}

/*
 * Return the number of keys stored in the node.
 * @return the number of keys in the node
 */
int BTLeafNode::getKeyCount()
{ 
	return NodePtr->Count;
}

/*
 * Insert a (key, rid) pair to the node.
 * @param key[IN] the key to insert
 * @param rid[IN] the RecordId to insert
 * @return 0 if successful. Return an error code if the node is full.
 */
RC BTLeafNode::insert(int key, const RecordId& rid)
{ 
	Rtuple temp;
	temp.Rid = rid;
	temp.key = key;
	int numcount = NodePtr->Count;
	if(numcount >= 84)
		return RC_NODE_FULL;
	int eid;
	if(locate(key, eid) == 0)
	{
		for(int k = numcount; k > eid; k--)
		{
			NodePtr->rtuples[k] = NodePtr->rtuples[k-1];
		}
		NodePtr->rtuples[eid] = temp;
		NodePtr->Count += 1;
	}
	else
	{
		NodePtr->rtuples[numcount] = temp;
		NodePtr->Count += 1;
	}
	return 0;
}

/*
 * Insert the (key, rid) pair to the node
 * and split the node half and half with sibling.
 * The first key of the sibling node is returned in siblingKey.
 * @param key[IN] the key to insert.
 * @param rid[IN] the RecordId to insert.
 * @param sibling[IN] the sibling node to split with. This node MUST be EMPTY when this function is called.
 * @param siblingKey[OUT] the first key in the sibling node after split.
 * @return 0 if successful. Return an error code if there is an error.
 */
RC BTLeafNode::insertAndSplit(int key, const RecordId& rid, 
                              BTLeafNode& sibling, int& siblingKey)
{ 
	Rtuple temp;
	temp.Rid = rid;
	temp.key = key;
	int eid;
	Rtuple rarray[85];
	if(locate(key, eid) == 0)
	{
		int k = 0;
		for(k; k < eid; k++)
			{rarray[k] = NodePtr->rtuples[k];}
		rarray[eid] = temp;
		for(k; k < 84; k++)
			{rarray[k+1] = NodePtr->rtuples[k];}
	}
	else
	{
		for(int k = 0; k < 84; k++)
		{rarray[k] = NodePtr->rtuples[k];}
		rarray[85] = temp;
	}
	int half = 85/2;
	for(int k = 0; k < half; k++)
		{NodePtr->rtuples[k] = rarray[k];}
	NodePtr->Count = half;
	for(int k = half; k < 85; k++)
		{sibling.insert(rarray[k].key, rarray[k].Rid);}
	siblingKey = rarray[half].key;
	return 0;
	
}

/*
 * Find the entry whose key value is larger than or equal to searchKey
 * and output the eid (entry number) whose key value >= searchKey.
 * Remeber that all keys inside a B+tree node should be kept sorted.
 * @param searchKey[IN] the key to search for
 * @param eid[OUT] the entry number that contains a key larger than or equalty to searchKey
 * @return 0 if successful. Return an error code if there is an error.
 */
RC BTLeafNode::locate(int searchKey, int& eid)		
{ 
	int numcount = NodePtr->Count;
	int k;
	for(k = 0; k <numcount; k++)
	{
		if(NodePtr->rtuples[k].key >= searchKey)
			break;
	}
	if(k == numcount)
		return RC_NO_SUCH_RECORD;
	else
	{
		eid = k;
		return 0;
	}
}

/*
 * Read the (key, rid) pair from the eid entry.
 * @param eid[IN] the entry number to read the (key, rid) pair from
 * @param key[OUT] the key from the entry
 * @param rid[OUT] the RecordId from the entry
 * @return 0 if successful. Return an error code if there is an error.
 */
RC BTLeafNode::readEntry(int eid, int& key, RecordId& rid)
{ 
	if(eid >= NodePtr->Count)
		return RC_NO_SUCH_RECORD;
	key = NodePtr->rtuples[eid].key;
	rid = NodePtr->rtuples[eid].Rid;
	return 0;
}

/*
 * Return the pid of the next slibling node.
 * @return the PageId of the next sibling node 
 */
PageId BTLeafNode::getNextNodePtr()
{ 
	return NodePtr->Nextkey;
}














/*
 * Set the pid of the next slibling node.
 * @param pid[IN] the PageId of the next sibling node 
 * @return 0 if successful. Return an error code if there is an error.
 */
RC BTLeafNode::setNextNodePtr(PageId pid)
{ 
	NodePtr->Nextkey = pid;
	return 0;
}


BTNonLeafNode::BTNonLeafNode()
{
	NodePtr = (nonLeafNode*)buffer;
	NodePtr->Count = 0;
	NodePtr->Firstkey = -1;

}	

/*
 * Read the content of the node from the page pid in the PageFile pf.
 * @param pid[IN] the PageId to read
 * @param pf[IN] PageFile to read from
 * @return 0 if successful. Return an error code if there is an error.
 */
RC BTNonLeafNode::read(PageId pid, const PageFile& pf)
{
	return pf.read(pid, buffer);
}
    
/*
 * Write the content of the node to the page pid in the PageFile pf.
 * @param pid[IN] the PageId to write to
 * @param pf[IN] PageFile to write to
 * @return 0 if successful. Return an error code if there is an error.
 */
RC BTNonLeafNode::write(PageId pid, PageFile& pf)
{ 
	return pf.write(pid, buffer);
}

/*
 * Return the number of keys stored in the node.
 * @return the number of keys in the node
 */
int BTNonLeafNode::getKeyCount()
{ 
	return NodePtr->Count;
}


/*
 * Insert a (key, pid) pair to the node.
 * @param key[IN] the key to insert
 * @param pid[IN] the PageId to insert
 * @return 0 if successful. Return an error code if the node is full.
 */
RC BTNonLeafNode::insert(int key, PageId pid)
{
	Ptuple temp;
	temp.Pid = pid;
	temp.key = key;
	int count = NodePtr->Count;
	if(count >= 127)
		return RC_NODE_FULL;
	int eid = 0;
	for(; eid < count; eid++)
	{
		if(NodePtr->ptuples[eid].key >= key)
			break;
	}
	
	for(int k = count; k > eid; k--)
		{NodePtr->ptuples[k] = NodePtr->ptuples[k-1];}
	
	NodePtr->ptuples[eid] = temp;
	NodePtr->Count += 1;
	
	return 0;
}

/*
 * Insert the (key, pid) pair to the node
 * and split the node half and half with sibling.
 * The middle key after the split is returned in midKey.
 * @param key[IN] the key to insert
 * @param pid[IN] the PageId to insert
 * @param sibling[IN] the sibling node to split with. This node MUST be empty when this function is called.
 * @param midKey[OUT] the key in the middle after the split. This key should be inserted to the parent node.
 * @return 0 if successful. Return an error code if there is an error.
 */
RC BTNonLeafNode::insertAndSplit(int key, PageId pid, BTNonLeafNode& sibling, int& midKey)
{
	Ptuple temp;
	temp.Pid = pid;
	temp.key = key;
	int eid = 0;
	Ptuple parray[128];
	
	for(; eid < 127; eid++)
	{
		if(NodePtr->ptuples[eid].key >= key)
			break;
	}
	int i = 0;
	for(; i < eid; i++)
	{
		parray[i] = NodePtr->ptuples[i];
	}
	parray[eid] = temp;
	for(; i < 127; i++)
	{
		parray[i+1] = NodePtr->ptuples[i];
	}
	int half = (128)/2;
	for(int k = 0; k < half; k++)
	{
		NodePtr->ptuples[k] = parray[k];
	}
	NodePtr->Count = half;
	midKey = parray[half].key;
	sibling.setLeftPtr(parray[half].key);
	for(int k = half+1; k < 128; k++)
	{
		sibling.insert(parray[k].key, parray[k].Pid);
	}
	return 0;
}

/*
 * Given the searchKey, find the child-node pointer to follow and
 * output it in pid.
 * @param searchKey[IN] the searchKey that is being looked up.
 * @param pid[OUT] the pointer to the child node to follow.
 * @return 0 if successful. Return an error code if there is an error.
 */
RC BTNonLeafNode::locateChildPtr(int searchKey, PageId& pid)
{
	int numcount = NodePtr->Count;
	if(numcount == 0)
	{
		pid = NodePtr->Firstkey;
		return 0;
	}
	int k;
	for(k = 0; k < numcount; k++)
	{
		if(NodePtr->ptuples[k].key > searchKey)
		{
			break;
		}
	}
	if(k == numcount)
	{
		pid = NodePtr->ptuples[numcount-1].Pid;
	}
	else
	{
		if(k == 0)
		{
			pid = NodePtr->Firstkey;
		}
		else
		{
			pid = NodePtr->ptuples[k-1].Pid;
		}
	}
	
	return 0;
}

/*
 * Initialize the root node with (pid1, key, pid2).
 * @param pid1[IN] the first PageId to insert
 * @param key[IN] the key that should be inserted between the two PageIds
 * @param pid2[IN] the PageId to insert behind the key
 * @return 0 if successful. Return an error code if there is an error.
 */
RC BTNonLeafNode::initializeRoot(PageId pid1, int key, PageId pid2)
{
	NodePtr->Firstkey = pid1;
	Ptuple temp;
	temp.key = key;
	temp.Pid = pid2;
	NodePtr->ptuples[0] = temp;
	NodePtr->Count = 1;
	
	return 0;
	
}


RC BTNonLeafNode::setLeftPtr(PageId left)
{
	NodePtr->Firstkey = left;
}


RC BTNonLeafNode::readEntry(int eid, int& key, PageId& rid)
{
	if(eid >= NodePtr->Count)
		return RC_NO_SUCH_RECORD;
	key = NodePtr->ptuples[eid].key;
	rid = NodePtr->ptuples[eid].Pid;
	return 0;
}

